Novel process for the preparation of trienic steroids and intermediates therein



United States Patent 976,020 16 Claims. (Cl. 260397.3)

The invention relates to a novel process for the preparation of 1 3fi-alkyl-A -gonatrienes of the formula wherein R is an alkyl radical of 1 to 4 carbon atoms. The invention also relates to novel intermediates formed therein.

The compounds of Formula I possess interesting pharmacological properties, particularly anabolic activity. For example, 17a-methyl-A -estratriene-17fi-o'l-3-0ne has remarkable ana'bolic and androgenic activity. The said compound has been prepared according to the process described in commonly assigned, copending US. application Serial No. 397,628, filed September 18, 1964 now US. Pat. 3,248,294, which comprises reacting A estratriene-17B-ol-3-one with hydroxylamine or a lower alkyl derivative thereof to form 3-oximido-A -estratriene-17fl-ol, oxidizing the latter by the Oppenauer reaction to form 3-oximido-A -estratriene-17-one, reacting the latter with a methyl magnesium halide to form 3 oximido-17a-methyl-A -estratriene-l7;3-ol and subjecting the latter to acidhy-drolysisu It is an object of the invention to provide a novel process for the preparation of 13fi-alkyl-17a-methy1- A -gonatrienes of Formula I,

I It is another object of the invention to provide novel intermediates for 13fi-alkyl-17a-methyl-A -gonatrienesof Formula I.

These and other objects and advantages of the invention will be obvious from the following detailed description.

The novel process of the invention 'for the preparation of 13B-alkyl-17a-methyl A -gontriene-l7 8-ol-3-ones of Eonmula I comprises reacting 13;3-alkyl-A -gonatriene- 3,17-dione wherein the alkyl has 1 to 4 carbon atoms with a derivative of hydrocyanic acid to form Bit-alkyl- 17a cyano-A -gonatriene-l7 3-ol-3-one, reacting the latter with a compound selected from the group consisting of hydroxylamine, lower alkylhy-droxylamine and acid addition salts thereof to [form the corresponding 3-oximido 13,8-akyl-17u-cyano-A -gonatriene-l7 3-ol, subjecting the latter to a compound selected from the group consisting of a basic agent and a weak organic acid .to form 3-oximdo-13 8-alkyl-A agonatriene-17-one, reacting the latter with. a methyl magnesium halide to form 3 oximido 13,6 alkyl-l7wmethyl-A -gonatriene- 1713-01 and subjecting the latter to acid hydrolysis to form 13 8 alkyl 17a methyl-A -gonatriene-17f3-ol-3-one. An outstanding feature of the process is the protection of 17-keto group in the .form of a cyanohydrin which is easily removed to obtain the 'free l7-keto group after oximida- 3,301,878 Patented Jan. 31, 1967 TABLE 1 R R OH I 1 UN R OH R RON= RON= R OH R on X on: i on,

RON o:

R is an alkyl of 1 to 4 carbon atoms and R is selected from the group consisting of hydrogen and lower alkyl of 1 to 7 carbon atoms.

The formation of the cyanohydrin grouping may be effected with derivatives of hydrocyanic acid such as alkali metal cyanides in the presence of acetic acid or cyanohydrins of ketones such as 2-cyano-propanol-2.

The oximidation of the 3-keto group may be efiiected with hydroxylamine or lower alkyl hydroxylamine or acid addition salts thereof in the presence of a lower alkanol and an alkali metal bicarbonate or in the presence of pyridine. i

The cyanohydrin group can be removed by reaction with a weak organic acid or a basic agent such as an alkali metal hydroxide in an aqueous lower alkanol. The

17-methylati0n may be eiiected with a methyl magnesium halide such as the bromide or iodide.

The removal of the 3-oximido group may be accomplished in aqueous media with a mineral acid such as sulfuric acid, hydrochloric acid, sulfurous acid, persul- I preferred embodiments to illustrate the invention. However, it should be understood that the invention is not to be limited to the specific embodiments.

EXAMPLE Preparaton of 17a-m'efhyl-A -estratriene-17/3-0l-3-0ne tion in the 3-pos1t1on. The reaction scheme is illustrated in Table I.

' cyano-A -estratriene-17 8-ol-3-one.

Step A: Preparation of J7a-cyano-A -estratriene- 17B-0l-3-0ne.-While working in total absence of light, 1.8 gm. of A -estratriene-3,17-dione were introduced into 5.4 cc. of 2-cyano-propanol-2 and 0.54 cc. of ammonia were added thereto. The mixture was agitated for a period of 17 hours at room temperature and then the reaction mixture was vacuum filtered, the precipitate was washed with ether and dried to obtain 1.6 gm. of 17a- This compound is not described in the literature.

In an analogous manner, 13,8-propyl-17u-cyano-A gonatriene-17/3-ol-3-one could be prepared from 13,B-propyl-A -gonatriene-3,17-dione.

Step B: Preparation of 3-0ximid0-17a-cyan0-A -estratriene-17fl-0l.While working in total absence of light, 415 mg. of hydroxylamine hydrochloride were introduced into 16 cc. of methanol. 502 mg. of sodium bicarbonate, 1.6 gm. of 17a-cyanO-A -estratriene-17/3-ol-3-one and a few cc. of water were added thereto and the mixture was heated at reflux for 1 /2 hours. The reaction mixture was then poured into ice water, vacuum filtered. The precipitate was washed and dried to obtain 3.5 gm. of raw, moist 3-oximido-17a-cyano-A -estratriene-175- 01 which was directly utilized for the next step.

This compound is not described in the literature.

In an analogous manner, 3-oximido-13 8-propyl-17acyano-A -gonatriene-17/3-01 could be prepared from 13,8-propyl-17a-cyano-A -gonatriene-17fi-ol-3-one.

Step C: Preparation of 3-0ximid0-A -estratriene-l7- one.--While working in total absence of light, 3.5 gm. of raw, moist 3-oximido-17a-cyano-A -estratriene-17,8- 01 were introduced into 16 cc. of methanol and a mixture of 4 cc. of water and 1.08 cc. of concentrated sodium hydroxide were added. The reaction mixture was heated at reflux for 1 hour and then was poured into ice water, neutralized by the addition of dilute acetic acid, allowed to stand for 1 hour at a temperature of C. and then vacuum filtered. The precipitate was Washed with water and dried to obtain 1.51 gm. of 3-oximido-A -estratriene-17-one having a melting point of 190 C. and a specific rotation [a] =+151i2 (c.=0.5% in ethanol).

Ultraviolet spectra:

The product was insoluble in water, ether and dilute aqueous acids and alkalis and was soluble in alcohol and chloroform.

This product is identical with the compound described in copending U.S. patent application Serial No. 397,628 filed September 18, 1964 now U.S. Pat. 3,248,294.

In analogous fashion, 3-oximido-13,8-propyl-A gonatriene-17-one could be prepared from 3-oximido- 13/3-propyl-l7ot-cyano-A -gonatriene-l73-01.

Step D: Preparation of 3-0ximid0-l7a-methyl-A estratriene-17fi-0l.--1.10 gm. of 3-oximido-A -estratriene-17-one in 60 cc. of benzene were added at room temperature and under an atmosphere of nitrogen to 300 cc. of 1.67 N methyl magnesium bromide in ethereal solution. hours and then cooled and 200 cc. of a saturated solution of ammonium chloride were added thereto. The mixture was extracted with ethyl acetate and the extract was washed with water and evaporated to dryness under vacuum. The residue was dissolved in methylene chloride and subjected to chromatography through magnesium silicate. The product was eluted with methylene chloride containing 1% of methanol, recrystallized from a benzenehexane mixture to obtain 0.97 gm. of 3-oximido 17a-methyl-A -estratriene-175-01 having a melting point of 135 C.

The product occurred in the form of pale yellow crystals soluble in acetone, benzene and chloroform.

n The product is identical to the compound described in U.S. patent application Serial No. 397,628.

In analogous fashion, 3-oximido-13fiapropyl-l7a-methyl-A -gonatriene-17B-ol could be prepared from 3- oximido-13,8-propyl-A -gonat-riene-17-one.

Step E: Preparation of 17ot-methyl-A -estratriene- 17 fl-0l-3-0ne.A mixture of 0.85 gm. of 3-oximido-17amethyl-A -estrat-riene-17,8-ol, 30cc. of acetic acid, 3 cc. of pyruvic acid and 30 cc. of distilled water was main- The reaction mixture was held at reflux for tained at reflux for 75 minutes with agitation and under a nitrogen atmosphere. The reaction mixture was cooled to room temperature, poured over an ice water mixture and sodium bicarbonate was added thereto. The mixture was vacuum filtered, washed with water and evaporated to dryness under vacuum. The residue -was dissolved in methylene chloride and passed through a column containing 25 gm. of magnesium silicate. Then the product was eluted with methylene chloride containing 2% of acetone to obtain 17a-methyl-A -estratriene-17,8-ol- 3-one which upon recrystallization from a methanolisopropyl ether mixture (1:4) had a melting point of 170 C. and a specific rotation [at] =58.7 (c.= 0.5% in ethanol).

This product occurred in the form of pale yellow crystals insoluble in water and dilute aqueous acids and alkalis and soluble in ether, acetone and benzene.

Analysis.-C H O Molecular weight=284.38. calculated: C, 80.24%; H, 8.50%. Found: C, 80.3%; H, 8.3%.

Ultraviolet spectra (EtO'I-I):

Infrared spectra: In accord with the proposed structure.

This compound is identical to that described in U.S. patent application Serial No. 697,628.

In analogous fashion, 13B-propyl-l7ot methyl-A gonatriene-17B-ol-3-one could be prepared from -3-oxirnido-13,8-propyl-17a-methyl-A -gonatriene-175-01.

Various modifications of the process of the invention may be made without departing 'from the spirit or scope thereof and it is to be understood that the invention is to be limited only as defined inthe appended claims.

We claim:

1. A process 'for the preparation of 13fi-alkyl-17a- I methyl-A -gonatriene-17fi-ol-3-ones of the formula R on V wherein R is an alkyl of 1 to 4 carbon atoms which comprises reacting wherein the alkyl has 1 to 4 carbon atoms with a derivative of hydrocyanic acid to form 13B-alkyl-17a-cyano- A -gonatriene-17B-o13-one, reacting the latter with a compound selected :from the group consisting of hydroxyl'amine, lower alkyl hydroxylamine and acid addition salts thereof to [form the corresponding 3-OXiIT1idO-13B- alkyl-17ot-cyano-A -gonatriene-17fl-ol, subjecting the latter to a compound selected from the group consisting of a basic agent and a weak organic acid to form 3-.

oximido-13,8-alkyl-A -gonatriene-17-one, reacting the latter with a methyl magnesium halide to form 3-oximido-l3/3-alkyl-17wmethyl-A -gon atriene 17p 01 and subjecting the latter to acid hydrolysis to form 13,B'-alkyl- 17a-methyl-A -gonatriene-17/i-ol-3one.

2. The process of claim 1 wherein the hydrocyanic acid is formed in the presence of an alkali metal bicarbonate in a lower alkanol.

5. The process of claim 1 wherein the 3-oximido group is formed in the presence of pyridine. 6. The process of claim 1 wherein the 3-oximid-o-13p- 13 5-alkyl-A -gonatriene-3,17-dione' alkyl-l7a-cyano-A -gonatriene-l75-01 is reacted with an aqueous lower alkanol solution of. an alkali metal hydroxide.

7. The process of claim 1 wherein the methyl magnesium halide is methyl magnesium bromide.

8. The process of claim 1 wherein the methyl magnesium halide is methyl magnesium iodide.

9. The process of claim 1 wherein the acid hydrolysis is effected with pyruvic acid in the presence of acetic acid.

10. The process of claim 1 wherein the starting material is A -estratriene-3,17-dione.

11. A process for the preparation of l7owrnethyl- A -estratriene-l7fl-ol-3-one which comprises reacting A -est'ratriene-3-17-dione with a hydrocyanic acid derivative to form l7a-cyano-A -estratriene-l7 8-ol-3- one, reacting the latter with a compound selected from the group consisting of hydroxylamine, lower alkyl hydroxylamine and acid addition salts thereof to form the corresponding 3 oximido-17a-cyano-A -estratriene- 176-01, subjecting the latter to a compound selected from the group consisting of a basic agent and a weak acid to form 3-oXimi do-A -estratriene-17-one, reacting the latter with a methyl magnesium halide to form 3-oXi-rnido- 17u-methyl-A -estratriene-17fi-ol and subjecting the latter to acid hydrolysis to form 17Ot-II1llhyl-A estratriene-17/3-ol-3one.

12. A process for the preparation of 3-oximido-1313 alkyl-A -gonatriene-17-one of the formula wherein R is an alkyl of 1 to 4 carbon atoms and R is selected from the group consisting of hydrogen and lower alkyl of 1 to 7 carbon atoms.

14. 3-oximido-17a-cyano-A -estnatriene-l7B-ol.

15. A compound of the formula R on wherein R is an alkyl of l to 4 carbon atoms.

16. 17a-cyano-A -estratriene-17/8-ol-3-one.

No references cited.

LEWIS GOTTS, Primary Examiner.

HENRY A. FRENCH. Assistant Examiner. 

12. A PROCESS FOR THE PREPARATION OF 3-OXIMIDO-13BALKYL-$4,9,11-GONATRIENE-17-ONE OF THE FORMULA 